The size of wireless communication devices is being driven by the marketplace towards smaller and smaller sizes. Consumer and user demand has continued to push a dramatic reduction in the size and weight of communication devices. To accommodate this trend, there is a drive to combine components and functions within the device, wherever possible, in order to reduce the volume of the circuitry. However, internal antenna systems still need to properly operate over multiple frequency bands and with various existing operating modes. For example, network operators providing service on the fourth generation Long Term Evolution (4G LTE) are also providing service on 3G systems, and the device must accommodate both these systems and their operating frequency bands.
The obvious solution is to provide separate antennas for each operating frequency band. However, this requires more room in the device, and conflicts with the technical requirements for enhanced operability of communication devices along with the drive for smaller device sizes.
What is needed is a communication device with an antenna structure that is contained internally within a single device housing, and that operates over multiple frequency bands, where the antenna structure is connected to a transceiver of the communication device by a single transmission line. The antenna must have high performance over a considerable bandwidth within each of the multiple frequency bands of operation, even where the frequency bands are not be harmonically related.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.